This invention relates to material handling and more particularly, to a multilevel conveyor section movable to different elevations.
Ongoing efforts to increase the efficiency and output of production operations have resulted in a continuing focus on how materials are moved in a manufacturing environment. In many environments, it is desirable to automatically move materials without human intervention. For example, parts are often buffered or temporarily stored in a material handler, for example, an automated parts buffer (xe2x80x9cAPBxe2x80x9d), an automated storage and retrieval system (xe2x80x9cASRSxe2x80x9d), etc.; and the parts are moved between the ASRS and part processing stations or equipment by material handlers, for example, an automated guided vehicle (xe2x80x9cAGVxe2x80x9d). In many applications, the AGV carries the parts in a stacked configuration, that is, at two different vertical levels or heights, thereby increasing the capacity and flexibility of the AGV. For example, being able to buffer or carry parts on conveyors on the AGV at two different heights, doubles the load carrying capacity of the AGV and permits an AGV to simultaneously transfer multiple parts with other part handling equipment, for example, an ASRS or a part processing station. Consequently, an AGV can transfer parts to or from, or simultaneously to and from, other part handling equipment. Thus, the AGV has significant flexibility in interfacing with other part handling equipment.
If an AGV must handle parts on conveyors at two different elevations, then the vertical distance separating the conveyors on the AGV must be the same as the vertical distance separating conveyors on the part handling equipment interfacing with the AGV. Commercial specifications of different equipment manufacturers facilitate obtaining a common separation between the conveyors on the AGV and its associated part handling equipment. However, the height or vertical position of the conveyors on the AGV with respect to a floor is often different from the vertical position of the conveyors on the part handling equipment associated with the AGV. Therefore, in transferring parts from stacked conveyors on the AGV, the parts must often be moved vertically up or down prior to the parts being at a height that matches the height of the conveyors on the associated part handling equipment.
If the vertical positions of the conveyors on the AVG and the vertical positions of the associated part handling equipment are different, then a direct transfer of parts between the AGV and the part handling equipment cannot occur. Under these conditions, in some applications, the parts are manually moved between the AGV to its associated equipment which is normally undesirable in an otherwise fully automated environment. In other applications, the parts are moved with inclined conveyors between the AGV and the associated part handling equipment. Inclined conveyors can take the form of linear or spiral conveyors, and both devices consume a significant area or floor space, thereby limiting their potential benefits and economies. Another option is to use a scissors lift. However, the requirement of providing a scissors lift with two vertically separated pass-through conveyors results in a scissors lift that is relatively complicated in design and expensive.
Consequently, there is a need for a material handling system that can transfer multiple parts from an AGV to associated part handling equipment having different elevations and that does not have the limitations and disadvantages of known devices.
The present invention provides a simple, compact, inexpensive and reliable elevatable conveyor section that may be used to interconnect existing conveyors having different heights. The elevatable conveyor section is especially useful for those applications in which floor space is at a premium, and it is desired to minimize the area consumed by the conveying elements.
According to the principles of the present invention and in accordance with the preferred embodiments, the invention provides an elevatable conveyor for moving articles between different material handling equipment. The elevator conveyor has a frame and a carriage supported by the frame which moves in a substantially vertical direction with respect to the frame. The carriage carries first and second conveyors capable of moving the material thereon and having different vertical locations on the carriage. A cylinder is connected to the frame, and the cylinder has a cylinder rod connected to the carriage. The cylinder is operable to move the carriage and the first and second conveyors in a substantially vertical direction between first and second vertical positions.
In one aspect of the invention, the conveyor elevator includes a first sensor for detecting a presence of an article on the first conveyor; and a second sensor for detecting a presence of an article on the second conveyor.
In another embodiment of the invention, a method is provided of transferring articles between first and second material handlers and first and second conveyors on a conveyor elevator. First, the conveyor elevator is located between the first and the second material handlers. Next, the first and second conveyors are moved in a vertical direction to a first vertical position aligning the first and second conveyors with the first material handler. Material is then transferred from the first material handler to the first conveyor of the elevator conveyor. The first and second conveyors are then moved in the vertical direction to a second vertical position aligning the first and second conveyors with the second material handler, and material is then transferred from the first conveyor of the elevator conveyor to the second material handler.
These and other objects and advantages of the present invention will become more readily apparent during the following detailed description taken in conjunction with the drawings herein.